Help Diagnosing Fuel Gauge Issues...

Ok so I got a tach cluster for my truck installed it. Everything worked fine, Speedo worked fine tach was accurate temp and fuel gauge worked fine. I filled up the tank and the gauge showed full. Drove the truck around for like 2 weeks. It never even crossed my mind that after about 320 miles I still had a quarter tank (or so the gauge said). At about 330 the truck just shut down... I was like shit... now what. Then I noticed I went 330 miles since the last gas stop... so it clicked! I’m out of gas! But the gauge says a quarter tank still...

I fill the tank and the gauge shows empty (below the E line) I took the cluster out. Took it apart cleaned it and installed it again. I set the gauge to full before I put it back in and the needle held there no problem. As soon as I turned the truck on the gauge went back to its previous spot, bellow E. I thought it was the gauge but I used my old cluster and it did the same thing...

What could be the issue? Does the gas tank have a float device or something and could have broken? Is it a replaceable part? Has this happened to anyone before? Thanks allot for the help in advanced

make sure your gas cap is sealed properly when i filled mine it went to e and i went to the smog guy he gave me a new cap and it went up to full again.... i remember hearing something about mazdas are known for this issue

really?... hmm ok im going to go try the fule cap from my RX7 on the truck and see if thats what it is... thats fucking WIERD... brb

hope it works, it tripped me out lol, i was like fucken a doggy my gauge works again lol

Nope that didnt Help at all

well damn it man lol, sorry worth a try at least, try disconnecting the battery for a few minutes, let the fuel sending unit reset? with the new cap on

Maz's are bad about wearing out the slide mechanism in the tank that reads fuel level.Unless u want to go to the trouble of dropping the tank and either cleaning the existing mechanism or replacing the fuel pump,I would just fill the truck up at 250 miles and forget it.Dropping the tank is a beautch.BJ

yeah i think im going to have to drop the tank then... haha im so anal about all my shit working. it just fucking drives me crazy. is there any information on what i need to clean or do?

Once you drop the tank, turn the ring on the top of the tank, then pull out the sending unit. Take a good look at how the float mech works. Best suggestion would be to hook up the sending unit to the wiring BEFORE putting it back in the tank - just to see how everything works.

Sorry, forgot Mazdas have screws holding the sending unit in, not a lock ring.